A French court has rejected a request by former IMF chief Dominique Strauss-Kahn to drop a sex offence inquiry in which he risks standing trial on pimping charges, his lawyers says.

The verdict came just over a week after Strauss-Kahn settled a separate civil case in New York with a hotel maid who accused him of attempted rape in May 2011, ending his presidential ambitions and career at the International Monetary Fund.

While the New York settlement brought his US legal woes to an end, Wednesday's decision by the court in Douai, in northern France, removed the prospect of a quick conclusion to the last sex offence inquiry he faces.

"Dominque Strauss-Kahn's defence team is certain that he will ultimately be cleared of these absurd accusations of pimping," lawyer Henri Leclerc said in a statement, adding that he planned to take the matter to France's supreme court.

Strauss-Kahn, once tipped to become president or France, is under fire over sex parties with prostitutes in the so-called Carlton Affair, named after a hotel in northern France at the centre of the inquiry.

His lawyers argue that consorting with prostitutes is not illegal and that investigators have no grounds for pursuing him on the grounds that his behaviour could be construed as pimping, which is illegal.